The lichenized mycobiota of Isla Mocha, southern Chile, includes 76 taxa in 30 genera; 38 % of the species are endemic to southern South America. Xanthoria parietina, found in all the collecting zones, and Pseudocyphellaria malmeana growing only on bark of Aextoxicon punctatum, are the most representative species. Ramalina fastigiata is a new record to Chile.